Following the Declaration, Jefferson served in the Virginia legislature. He focused on reforming Virginia laws to align with republican principles, including abolishing primogeniture and entail, promoting religious freedom, and establishing a public education system. These reforms aimed to dismantle aristocratic privileges and promote equality.

Jefferson served as Governor of Virginia during a critical period of the Revolutionary War. He faced significant challenges in supplying and defending Virginia against British incursions. His leadership during this period was later criticized for perceived inadequacies in responding to British raids, particularly Benedict Arnold's invasion.

In 1781, British forces under Benedict Arnold invaded Virginia, causing widespread disruption. Jefferson was forced to flee Monticello to avoid capture. This event led to a legislative inquiry into his conduct as governor, which though ultimately cleared him, it left a lasting impact on his reputation.

Martha Wayles Jefferson died after a long illness. Her death deeply affected Jefferson, who was reportedly devastated by the loss of his wife. He never remarried and took great pains to protect her memory. This deeply personal loss undoubtedly impacted his perspective on life and politics.